Inspired by this post by Gayla Trail and stocking up on squash blossoms while they're cheap at the farmers market, I decided to do a quick-and-dirty experiment. I kept one bunch in the refrigerator in a sealed glass jar with no water and another bunch in a jar on the counter with the stems in some water overnight.
It's kind of a terrible picture since it's taken at night in my kitchen but I think you can tell that the refrigerated blossoms were in much better shape! The countertop blossoms are shriveled and dry - and one has even fallen off its stem while the ones from the refrigerator are still fresh and pliant. I'll be storing my squash blossoms in the refrigerator from now on.